Return-Path: Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 744224 for flyrotary@lancaironline.net; Fri, 18 Feb 2005 09:46:08 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.68; envelope-from=sqpilot@bellsouth.net Received: from [209.214.44.51] by imf20aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050218144508.OUKY1977.imf20aec.mail.bellsouth.net@[209.214.44.51]> for ; Fri, 18 Feb 2005 09:45:08 -0500 Received: from 127.0.0.1 (AVG SMTP 7.0.300 [265.8.8]); Fri, 18 Feb 2005 08:44:50 -0600 Message-ID: <002d01c515c8$5fab9510$332cd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] induction scoop Date: Fri, 18 Feb 2005 08:44:36 -0600 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=======AVGMAIL-4215FF6233FD=======" --=======AVGMAIL-4215FF6233FD======= Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C51596.13830B00" ------=_NextPart_000_002A_01C51596.13830B00 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi, Al....GREAT job on your induction scoop. I think I can come up with = something similar. Thanks again....a picture is worth a thousand words. = Paul Conner ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Thursday, February 17, 2005 9:59 AM Subject: [FlyRotary] induction scoop Paul C wrote: I was thinking of installing two small NACA ducts on the bottom of my = cowling with two hoses coming up to feed air to my TWM throttlebody. = The NACA ducts I purchased from Van's RV (made for cowling ventilation) = already have a male outlet already molded in the assembly, so you just = slide a hose over it and secure with a clamp --------------------------------------------- Paul; It would be better to have a single inlet if it can work to minimize = flow losses. The inlet area should be at least 4-5 sq in, and then that = area should expand to about to maybe 4" diameter before the TB entrance = for pressure recovery. A NACA scoop near the back of the plane isn't = going to get you much in the way of ram effect; but even the best ram = scoop is only going to get you about 0.3 - 0.4 psi boost at cruise. = Just getting some unencumbered cool air in there is going to help. Induction scoops are a bit tricky because when you start your takeoff = roll the inflow is completely dependant upon being "sucked" in, and = you'd like to have minimum entrance loss. At high speed you want a = scoop design that maximizes the ram pressure, with minimum drag. The = two conditions are at odds. The best compromise is a ram scoop with a well rounded entrance lip; = about a finger radius. Attached photo is my shot at a ram scoop. Al -------------------------------------------------------------------------= ----- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: 2/14/2005 ------=_NextPart_000_002A_01C51596.13830B00 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Hi, Al....GREAT job on your induction = scoop. =20 I think I can come up with something similar.  Thanks again....a = picture is=20 worth a thousand words.  Paul Conner
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Thursday, February 17, = 2005 9:59=20 AM
Subject: [FlyRotary] induction=20 scoop

Paul C wrote:

 

 I was thinking of installing two small = NACA=20 ducts on the bottom of my cowling with two hoses coming up to feed air = to my=20 TWM throttlebody.  The NACA ducts I purchased from Van's RV (made = for=20 cowling ventilation) already have a male outlet already molded in the=20 assembly, so you just slide a hose over it and secure with a=20 clamp

 

---------------------------------------------

 

Paul;

 

It would = be better=20 to have a single inlet if it can work to minimize flow losses.  = The inlet=20 area should be at least 4-5 sq in, and then that area should expand to = about=20 to maybe 4" diameter before the TB entrance for pressure = recovery.  A=20 NACA scoop near the back of the plane isn=92t going to get you much in = the way=20 of ram effect; but even the best ram scoop is only going to get you = about 0.3=20 =96 0.4 psi boost at cruise.  Just getting some unencumbered cool = air in=20 there is going to help.

 

Induction scoops=20 are a bit tricky because when you start your takeoff roll the inflow = is=20 completely dependant upon being "sucked" in, and you'd like to have = minimum=20 entrance loss.  At high speed you want a scoop design that = maximizes the=20 ram pressure, with minimum drag.  The two conditions are at=20 odds.

 

The best = compromise is a ram scoop with a well rounded entrance lip; about a = finger=20 radius. Attached photo is my shot at a ram scoop.

 

Al

 

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 http://lancaironline.net/lists/flyrotary/List.html

No virus found in this incoming message.
Checked by AVG=20 Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - Release = Date:=20 2/14/2005
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